The response of a bone resorption marker to Marine recruit training

Objectives: This study measured the response of deoxypyridinoline, a biomarker of bone resorption, during 11 weeks of Marine recruit training. Methods: Urine samples were obtained from 155 female and 58 male Marine recruits from the first morning void every 3 days during training. Training miles of weight-bearing exercise were recorded daily, and injury data were obtained from the medical clinic staff. Results: Deoxypyridinoline was significantly (p < 0.001) increased at week 2 and weeks 9 through 11 for women and at weeks 10 and 11 for men. The increase in bone resorption corresponded to an increase in miles of weight-bearing exercise performed throughout training. The incidence of stress fracture and reaction was 3.9% and 14.8%, respectively, for women and 1.7% and 3.4%, respectively, for men. Conclusions: Significant bone resorption took place at the end of Marine recruit training due to accumulation of weight-bearing exercise throughout training and the increase in marching toward the end.